The invention relates to a wheel, in particular for mobile apparatus such as carriages or the like, and a method for realising the wheel.
In particular, the invention relates to a small wheel, generally used for mobile apparatus for domestic use, such as for example: floor-washers, vacuum cleaners, small carriages etc.
The wheels, which normally exhibit a minimum diameter of 200 mm, are constituted by a central hub and an external covering defining the tread of the wheel.
In greater detail, the hub is made of a thermoplastic material and has a substantially discoid shape. A scalloping develops on the annular external surface of the hub, destined to anchor the covering to the central hub.
The scalloping is constituted by a series of portions projecting radially from the external surface of the hub and developing at a central zone of the external surface.
The covering is made of a thermoplastic material, injection-moulded on the external surface of the hub.
The thermoplastic material, in a liquid state, is distributed on the external surface and about the scalloping, such as to be anchored to the externally-projecting portions.
At the end of the moulding stage, the solidified thermoplastic material is distributed over all the peripheral zone of the hub in order to define the tread of the wheel.
The above-described wheels, and the method for realising the wheels, exhibit however important drawbacks.
Firstly, the radially-projecting elements, though facilitating the anchoring of the tread to the wheel, constitute all the same an obstacle for the laying of the molten thermoplastic material.
The material injected on the external surface of the hub is obstructed by the scalloping which prevents a homogeneous distribution of the material over all the annular external surface of the hub.
Consequently a tread is realised which has a non-uniform conformation, provided with some zones having variable conformation and other zones having a variable thickness which lead to damaging vibrations during the rolling of the wheel.
In this context, the technical aim at the basis of the present invention is to provide a wheel for mobile apparatus such as carriages or the like and a method for realising the method, which obviates the drawbacks of the prior art as cited above.
In particular, an aim of the present invention is to provide a wheel having a tread that is well-anchored to the hub and homogeneously distributed over all of the external surface of the hub.
A further aim of the present invention is to provide a wheel and a method for realising the method which is able to facilitate the injection operations of the tread on the periphery of the wheel.
The set technical objective and the specified aims are substantially attained by a wheel, in particular for mobile apparatus such as carriages or the like, and by a method for realising the wheel comprising the technical characteristics set out in one or more of the accompanying claims.